Shared ownership was sold as an alternate route out of the private rented sector and into home ownership for those locked out of the housing market, but a report from Cambridge University has found that this dream of complete ownership is rarely realised for shared owners.

Shared ownership helps people onto the housing ladder by allowing them to part-purchase a home and then gradually increase their share – or "staircase" up – to achieve full ownership. The scheme has been particularly attractive to first-time buyers and others struggling to raise a large enough mortgage or deposit for an outright purchase.

Under shared ownership, buyers take out a mortgage on part of a property and pay rent to a housing association on the remaining share. Buyers can then increase their share of ownership gradually as their circumstances change and they can afford it.

Or not. The Cambridge study, commissioned by Thames Valley Housing, found that since 2001 only 27,908 (19%) of the 145,000 homes bought through a shared ownership scheme had been staircased up to 100% ownership.

The report says: "Although regularly portrayed as a 'stepping stone' into ownership, for the majority of existing shared owners shared ownership is a tenure for the long term. Indeed, many never achieve full ownership. This is possibly inevitable given the policy objective of prioritising those least able to afford full owner-occupation."

Decreases in property value have seen some residents complain of becoming "trapped" in their part-owned properties. The scheme has also come under criticism for the lack of legal recourse it offers buyers, the lack of supporting legislation from government and the difficulty in completing second-hand sales.

Is shared ownership still the answer for people needing help to get onto the property ladder? Or is it time for the housing sector to design a new alternative?

Join our panel of experts from 12pm on Monday 16 July to take part in the discussion, or leave a question or comment in advance now.

PanelJames Cartlidge is a founder and director of Share to buy, a portal where you can search for shared ownership properties and mortgages

Sally Lynch is the head of space property and development at Yorkshire Housing, a charitable organisation with over 16,000 properties in Yorkshire. Yorkshire Housing are the HomeBuy agent for West Yorkshire, North Yorkshire and the Humber. They have approximately 1,000 leaseholders

Leonie Brown lives in a shared ownership flat in Hackney, East London. She bought a 40% share in the two-bedroom new build property last year, and lives there alone. She works in the voluntary sector

Steve Michaux is director of leasehold services for A2Dominion Housing Group and chairs groups looking at shared ownership management on behalf of London housing associations and the National Housing Federation. A2Dominion currently has over 4,000 shared ownership properties and 2,700 leasehold properties in its portfolio

Trudy Quinn manages Peabody's affordable homes sales programme, part of her remit has lead for the sales and marketing team responsible for delivering Peabody's shared ownership and private sales as well as sales of existing shared ownership. She is also secretary of London Home Ownership Group (LHOG)

Ben Clay is the director of HomesHub, Plus Dane Group's affordable home ownership and intermediate housing arm. HomesHub is also the government's local HomeBuy agent for Merseyside and Cheshire. Ben has extensive experience in developing, selling and managing shared ownership homes